Usually shaving early in the morning before work with the rest of the house asleep, so it's as quiet as I can make it. On weekends, though, it's usually David Bowie, Warren Zevon, Florence + the Machine, Metallica, Ozzy or In This Moment, depending on the time of day and mood.
Tonight, though, was my first go with a straight razor and it ended up being Van Morrison's Astral Weeks. Wonderfully mellow after a LONG day of yard and house work.